A grading process for hydrocracking catalyst and oil hydrocracking method

Abstract

The present invention provides a grading process of oil hydrocracking catalyst and an oil hydrocracking method, comprising: along the material flow direction in the hydrogenation reactor, sequentially filling a protective layer and a catalyst layer in the hydrogenation reactor; the protective layer comprises a protective agent, and the pore volume of the protective agent in the protective layer tends to decrease along the material flow direction in the hydrogenation reactor; the catalyst layer comprises a catalyst, and the total acid amount of the catalyst in the catalyst layer tends to increase along the material flow direction in the hydrogenation reactor; the ratio of the sum of the acid amount of strong acid and medium-strong acid to the total acid amount tends to increase along the material flow direction in the hydrogenation reactor; the main active metal content in the catalyst tends to increase along the material flow direction in the hydrogenation reactor. The present invention can improve the liquid yield of the oil to be treated, increase the yield of kerosene and naphtha, reduce the yield of gas products, and maximize the economic benefits of the device.

Description

Technical Field

[0001] The invention relates to a grading process of a hydrocracking catalyst and an oil hydrocracking method, belonging to the technical field of oil hydrocracking. Background Art

[0002] As a non-renewable resource, the utilization of petroleum resources is tending towards heavy and inferior quality. On the other hand, with the improvement of clean oil standards, the requirements for the quality and cleanliness of petroleum fuel products are becoming increasingly stringent. Therefore, it is urgent to lighten heavy crude oil and other oil products and efficiently convert them into clean oil products.

[0003] Hydrocracking technology is one of the important technologies for producing high-quality clean finished oil products. It has unique advantages such as strong raw material adaptability, flexible processing schemes, and good product quality. The product has high cleanliness, and impurities such as sulfur and nitrogen meet the National VI fuel oil standards. The quality of aviation kerosene is high and can be directly used as military aviation fuel. Heavy naphtha has a high potential content of aromatics and is a high-quality raw material for catalytic chemical production of aromatics or high-octane gasoline. At the same time, it can also produce clean diesel blending components that meet the National VI standards. Hydrocracking technology has gradually developed into a key secondary processing technology for modern refining and chemical companies to produce clean oil products and high-quality chemical raw materials.

[0004] The hydrocracking catalysts used in industrial applications mainly include alumina, molecular sieves, active metals and silicon-alumina oxides, of which alumina, molecular sieves and silicon-alumina oxides form carriers. The main function of the carriers is to provide suitable acidic sites during the hydrocracking reaction to promote the chemical bond breaking of heavy oil molecules and provide abundant specific surface area. Active metals mainly provide hydrogenation functions.

[0005] The existing hydrocracking technology mainly focuses on developing efficient hydrocracking supports and catalysts.

[0006] CN111318313A discloses a hydrocracking catalyst carrier and its preparation method and application, wherein the carrier contains Y molecular sieve and SAPO-34 molecular sieve, and the weight content of Y molecular sieve is 2wt% to 35wt% and the content of SAPO-34 molecular sieve is 2wt% to 25wt% based on the carrier. The catalyst prepared by the carrier has high reaction activity, medium oil selectivity and excellent product properties in the hydrocracking reaction process. However, the technology does not optimize the acidity of SAPO-34 molecular sieve, and the carbon deposition rate of SAPO-34 is relatively high, which is not conducive to meeting the requirements of long-term stability of catalysts in industrial applications.

[0007] WO2020119754A1 discloses a hydrocracking catalyst and its preparation method and application. The catalyst in the patent includes a carrier, silica loaded on the carrier and an active component, wherein the carrier contains Y molecular sieve and SAPO-34 molecular sieve. The method for preparing the hydrocracking catalyst includes acid optimization of SAPO-34 molecular sieve, but only silane is used as a regulator in the synthetic material, which is costly and not conducive to reducing catalyst costs and popularizing industrialization.

[0008] CN105709844A discloses a hydrocracking catalyst carrier and a preparation method thereof. The catalyst carrier adopts a modified Y-type molecular sieve and a β molecular sieve as a cracking center, wherein the Y-type molecular sieve used is a Y-type molecular sieve with large grains, high silicon and concentrated effective pore size distribution. The hydrocracking catalyst prepared from the Y-type molecular sieve is used in the hydrocracking process of producing more high-quality intermediate distillate oil products, and has the characteristics of high activity and good selectivity, but the catalyst has low selectivity for aviation kerosene.

[0009] CN104667969B The invention discloses a hydrocracking catalyst and a preparation method thereof. The catalyst comprises a β molecular sieve, a Y-type molecular sieve and an alumina carrier. The hydrocracking catalyst has the characteristics of suitable silicon-aluminum ratio, large specific surface area, suitable acidity, reasonable pore structure and low non-framework aluminum content. The prepared catalyst can be used to produce more low-freezing point diesel and improve the properties of chemical raw materials, but the oil selectivity of the catalyst is relatively low.

[0010] Although there are many reports on the carrier and catalyst preparation process of hydrocracking catalysts in the prior art, there are few studies on the grading process of hydrocracking catalysts, which ignores the important role of the grading process of hydrocracking catalysts in improving the distribution of products. Summary of the invention

[0011] The present invention provides a hydrocracking catalyst grading process and a hydrocracking method. By using a specific protective agent and a catalyst grading method, the total liquid yield and the light product (kerosene and naphtha) yield, especially the naphtha yield, can be effectively improved, thereby overcoming the problem that the existing hydrocracking catalyst has a low naphtha yield.

[0012] The present invention provides a grading process for a hydrocracking catalyst, which comprises:

[0013] In the present invention, starting from the loading aspect of the catalytic system in the hydrogenation reactor, the protective agent (protective layer) and the catalyst (catalyst layer) are loaded in sequence along the material flow direction of the hydrogenation reactor.

[0014] The protective layer includes a protective agent, and the pore volume of the protective agent in the protective layer tends to decrease along the material flow direction in the hydrogenation reactor;

[0015] The catalyst layer includes a catalyst, and the total acid amount of the catalyst in the catalyst layer shows an increasing trend along the material flow direction in the hydrogenation reactor; the proportion of the sum of the acid amounts of strong acid and medium-strong acid to the total acid amount shows an increasing trend along the material flow direction in the hydrogenation reactor.

[0016] The content of the main active metal in the catalyst tends to increase along the material flow direction in the hydrogenation reactor.

[0017] The method as described above, wherein the pore volume of the protective agent in the protective layer gradually decreases or decreases gradiently along the material flow direction in the hydrogenation reactor; and / or the specific surface area of ​​the protective agent in the protective layer tends to increase along the material flow direction in the hydrogenation reactor, preferably, the increasing trend includes a gradual increase or a gradient increase.

[0018] In the method as described above, the total acid amount of the catalyst in the catalyst layer shows a trend of gradual increase or gradient increase along the material flow direction in the hydrogenation reactor.

[0019] The method as described above, wherein the pore volume of the protective agent is not less than 0.5 ml / g.

[0020] According to the method described above, the protective agent includes a carrier and a main active metal, wherein the mass percentage of the main active metal in the protective agent is 0 to 10%; the main active metal in the protective agent is selected from one or more of nickel, cobalt, molybdenum, and tungsten; and / or the protective agent carrier includes an amorphous porous material, preferably, the amorphous porous material includes one or more of alumina, amorphous silica aluminum (ASA), titanium dioxide, zirconium dioxide, silicon dioxide, Al2O3-SiO2 composite oxide, Al2O3-TiO2 composite oxide, Al2O3-ZrO2 composite oxide, ZrO2-TiO2 composite oxide, and TiO2-SiO2 composite oxide; and / or, the mass percentage of the main active metal of the protective agent in the protective layer remains unchanged or shows an increasing trend along the material flow direction in the hydrogenation reactor, preferably, the increasing trend includes a gradual increase or a gradient increase.

[0021] According to the method as described above, the catalyst comprises a carrier and a main active metal, wherein the carrier comprises an amorphous porous material and a molecular sieve, preferably, the amorphous porous material comprises one or more of alumina, amorphous silica-alumina, titanium dioxide, zirconium dioxide, silicon dioxide, Al2O3-SiO2, Al2O3-TiO2 composite oxide, Al2O3-ZrO2 composite oxide, ZrO2-TiO2 composite oxide, TiO2-SiO2 composite oxide; the molecular sieve comprises one or more of Y molecular sieve, ZSM-5, ZSM-22, ZSM-23, ZSM-35, Beta, ZSM-48; preferably, the catalyst The mass percentage of the amorphous porous material in the catalyst is 5-27%, the mass percentage of the molecular sieve in the catalyst is 50-70%; the mass percentage of the main active metal in the catalyst is 20-40%; and / or the main active metal in the protective agent is selected from one or more of nickel, cobalt, molybdenum, and tungsten; and / or the pore volume of the catalyst is 0.2-0.6 ml / g; and / or the catalyst also includes an acidic additive, wherein the mass percentage of the acidic additive in the catalyst is 0.5-3%, and / or the acidic additive comprises one or more of phosphoric acid, boric acid, hydrofluoric acid, nitric acid, citric acid, tartaric acid, and malic acid.

[0022] According to the method described above, the total acid amount of the catalyst in the catalyst layer is 100 to 500 μmol / g; and / or the strong acid amount of the catalyst in the catalyst layer is 30 to 150 μmol / g; and / or the strong acid amount in the catalyst in the catalyst layer is 50 to 300 μmol / g; and / or the strong acid amount in the catalyst in the catalyst layer is greater than the strong acid amount.

[0023] According to the method described above, the ratio of the sum of the acid amounts of the strong acid and the medium-strong acid to the total acid amount shows a trend of gradually increasing or gradient increasing along the material flow direction in the hydrogenation reactor.

[0024] In the above method, the volume of the protective layer accounts for 2-20% of the sum of the volume of the protective layer and the volume of the catalyst layer, and / or the volume of the catalyst layer accounts for 80-98% of the sum of the volume of the protective layer and the volume of the catalyst layer.

[0025] The method as described above is a method for hydrocracking of oil products based on the above-mentioned grading method for loading, comprising: allowing the oil product to be treated to enter a hydrogenation reactor and contact it with a protective agent and a catalyst for hydrocracking, wherein the flow direction of the oil product to be treated in the hydrogenation reactor is the material flow direction in the hydrogenation reactor.

[0026] The conditions of the hydrocracking treatment are as follows: reaction pressure of 6-15 MPa, reaction temperature of 300-400°C, volume space velocity of 0.5-2.0 h -1 , the volume ratio of hydrogen to oil is (100-1000):1;

[0027] And / or, the oil product to be treated includes one or more of coker gas oil (CGO), vacuum gas oil (VGO), coker diesel and wax oil; and / or, the sulfur content in the oil product to be treated is not more than 1000 μg / g; and / or, the nitrogen content in the oil product to be treated is not more than 20 μg / g.

[0028] By adopting the hydrocracking catalyst grading process of the present invention to load the protective agent and the catalyst, the total liquid yield of the device can be improved, the yield of the gas product can be reduced, and the product distribution can be effectively improved to generate more light products (kerosene and naphtha). In particular, naphtha is used as a high-quality ethylene cracking raw material, and the naphtha yield is greatly improved, which can effectively improve the economic benefits of the device. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below. The specific implementation methods listed below are only for describing the principles and features of the present invention. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0030] Hydrocracking technology has become one of the key core technologies for producing high-quality light oil products, and the focus of hydrocracking technology is on the research and development of catalysts. Hydrocracking catalysts are mainly composed of carriers and main active metals. The main active metals can be VIB group or VIII group metals, specifically metal oxides or metal sulfides, etc. The carrier is generally alumina. Due to the limitations of alumina pore size and surface acidity, catalysts that use alumina as a carrier alone cannot achieve deep polycyclic aromatic hydrocarbon saturation and removal of heterocyclic nitrides.

[0031] Therefore, according to the inventor's research, for further development of the catalyst, in addition to improving the pore structure of the carrier and adjusting the interaction between the carrier and the metal, it is also necessary to optimize the surface acid structure of the hydrogenation catalyst. The increase in the acid content of the catalyst is conducive to improving the cracking of liquid products, but the increase in the proportion of weak acid in the catalyst is not conducive to improving the cracking activity of oil products. The strong acid content and medium-strong acid content in the catalyst really play a leading role. Depending on the preparation process, there may be two types of acid centers on the hydrocracking catalyst, namely acid center and Lewis acid center, the total acid content of the catalyst is The sum of the acid amounts of Bronsted acid and Lewis acid. The Bronsted acid center can provide protons, while the Lewis acid center can accept unpaired electrons. The existing technology mainly optimizes the acidity at the catalyst particle scale. The catalyst has poor catalytic selectivity, resulting in a low yield of light oil products. However, there are few methods that use the grading process to coordinate the acidity of the catalyst to achieve the purpose of improving the hydrocracking effect.

[0032] In view of this, an embodiment of the present invention provides a grading method for a hydrocracking catalyst, comprising:

[0033] A protective agent (protective layer) and a catalyst (catalyst layer) are sequentially loaded along the material flow direction of the hydrogenation reactor; the protective layer includes a protective agent, and the pore volume of the protective agent in the protective layer tends to decrease along the material flow direction in the hydrogenation reactor; the catalyst layer includes a catalyst, and the total acid content of the catalyst in the catalyst layer tends to increase along the material flow direction in the hydrogenation reactor; the proportion of the sum of the acid content of strong acid and medium-strong acid to the total acid content tends to increase along the material flow direction in the hydrogenation reactor; the content of the main active metal in the catalyst tends to increase along the material flow direction in the hydrogenation reactor.

[0034] Through the above-mentioned grading method, the cracking performance of the overall catalytic system formed by the protective layer and the catalyst layer in the hydrogenation reactor can be improved, and the liquid yield of light oil products can be improved, thereby improving the overall operating economy of the hydrogenation reactor / device.

[0035] After research and analysis, the inventor believes that in the above-mentioned grading method, reasonable grading filling is carried out based on the use functions of the protective agent and the catalyst. The protective agent can be used to perform preliminary impurity removal on the material (such as the oil to be processed) entering the hydrogenation reactor, such as removing mechanical impurities and at least part of the metals, and the catalyst layer further performs deep hydrogenation cracking on the material, wherein the main active metal in the catalyst tends to increase along the material flow direction, so that the hydrogenation activity of the catalyst tends to increase along the material flow direction, which can slowly increase the hydrogenation activity of the catalyst and control the temperature rise of the bed in the hydrogenation reactor, which is conducive to the hydrogenation reaction; at the same time, the total acid content of the catalyst layer tends to increase along the material flow direction, and the proportion of the sum of the strong acid and the medium-strong acid to the total acid content of the catalyst tends to increase along the material flow direction, so that the catalyst cracking activity slowly increases, ensuring the deep ring-opening cracking activity of the oil product, so as to facilitate the production of more high-quality light oil products, especially the naphtha yield is greatly improved. Therefore, through the above-mentioned grading method, the overall catalytic performance of the catalytic system formed by the protective agent and the catalyst can be effectively exerted, the deep cracking activity of the catalytic system can be improved, and the liquid yield of light oil products can be improved.

[0036] Specifically, the hydrogenation reactor can be placed vertically, and the material flow direction in the hydrogenation reactor can be from top to bottom of the hydrogenation reactor (i.e., from the upper part / top of the hydrogenation reactor to the lower part / bottom of the hydrogenation reactor).

[0037] The decreasing trend as described above may include a gradual decrease or a gradient decrease (or step decrease), that is, the pore volume of the protective agent in the protective layer may be gradually decreased or gradient decreased along the material flow direction in the hydrogenation reactor.

[0038] Specifically, the protective layer may include at least two protective sublayers sequentially distributed along the material flow direction in the hydrogenation reactor, and the pore volume of the protective agent in each protective sublayer may remain unchanged or show a decreasing trend along the material flow direction. In some specific embodiments, of two adjacent protective sublayers, the pore volume of the protective agent in the upstream one is greater than the pore volume of the protective agent in the downstream one, and the direction from upstream to downstream is the material flow direction in the hydrogenation reactor, that is, the pore volume of the protective agent in the sublayer closer to the catalyst layer is smaller, thereby causing the pore volume of the protective agent in the protective layer to decrease gradually along the material flow direction in the hydrogenation reactor.

[0039] In some specific embodiments, the protective layer includes two protective sublayers, which are respectively a first protective sublayer and a second protective sublayer, which are sequentially distributed along the material flow direction of the hydrogenation reactor. That is, the first protective sublayer, the second protective sublayer, and the catalyst layer are sequentially distributed along the material flow direction in the hydrogenation reactor, and the pore volume of the protective agent in the first protective sublayer is greater than the pore volume of the protective agent in the second protective sublayer.

[0040] Specifically, the pore volume of the protective agent may be not less than 0.5 ml / g, and further may be not less than 0.6 ml / g. Exemplarily, the pore volume of the protective agent is, for example, 0.6 ml / g, 0.7 ml / g, 0.8 ml / g, 0.9 ml / g, 1 ml / g, or a range consisting of any two thereof.

[0041] It is understood that when the protective layer includes at least two protective sublayers (such as a first protective sublayer and a second protective sublayer), the pore volume of the protective agent in each sublayer is not less than 0.5 ml / g, and may further be not less than 0.6 ml / g.

[0042] Specifically, the difference in pore volume of the protective agent in two adjacent protective sublayers (such as the difference in pore volume of the protective agent in the first protective sublayer and the pore volume of the protective agent in the second protective sublayer) can be, for example, 0.1 to 0.5 ml / g, such as 0.1 ml / g, 0.2 ml / g, 0.3 ml / g, 0.4 ml / g, 0.5 ml / g or a range composed of any two thereof, but is not limited thereto.

[0043] Exemplarily, the pore volume of the first protective sublayer is greater than 0.6 ml / g, for example, 0.65 ml / g to 1.0 ml / g, and the pore volume of the second protective sublayer is less than 0.6 ml / g, for example, 0.5 ml / g to 0.59 ml / g.

[0044] Generally, the specific surface area of ​​the protective agent in the protective layer tends to increase along the material flow direction in the hydrogenation reactor. The increasing trend may include a gradual increase or a gradient increase (or called a step increase or a step increase), that is, the specific surface area of ​​the protective agent in the protective layer may gradually increase or increase in a gradient along the material flow direction in the hydrogenation reactor.

[0045] In the at least two protective sublayers, the specific surface area of ​​the protective agent in each protective sublayer may remain unchanged or increase along the material flow direction. In some specific embodiments, in two adjacent protective sublayers, the specific surface area of ​​the protective agent in the upstream one is smaller than the specific surface area of ​​the protective agent in the downstream one, that is, the specific surface area of ​​the protective agent in the protective sublayer closer to the catalyst layer is larger, thereby causing the specific surface area of ​​the protective agent in the protective layer to increase gradually along the material flow direction in the hydrogenation reactor.

[0046] For example, the specific surface area of ​​the protective agent in the first protective sublayer is smaller than the specific surface area of ​​the protective agent in the second protective sublayer.

[0047] Specifically, the specific surface area of ​​the protective agent can be 100 to 200 m 2 / g, for example 100m 2 / g, 110m 2 / g, 120m 2 / g, 130m 2 / g, 140m 2 / g, 150m 2 / g, 160m 2 / g, 170m 2 / g, 180m 2 / g, 190m 2 / g, 200m 2 / g or a range consisting of any two thereof.

[0048] It is understood that when the protective layer includes at least two protective sublayers (such as a first protective sublayer and a second protective sublayer), the specific surface area of ​​the protective agent in each sublayer can be 100 to 200 m 2 / g.

[0049] Specifically, the difference in specific surface area of ​​the protective agent in two adjacent protective sublayers (such as the difference in specific surface area of ​​the protective agent in the first protective sublayer and the specific surface area of ​​the protective agent in the second protective sublayer) can be, for example, 10 to 50 m 2 / g, such as 10m 2 / g, 12m 2 / g, 15m 2 / g, 18m 2 / g, 20m 2 / g, 20m 2 / g, 25m 2 / g, 30m 2 / g, 35m 2 / g, 40m 2 / g, 45m 2 / g, 50m 2 / g or a range consisting of any two of them, but is not limited thereto.

[0050] Exemplarily, the specific surface area of ​​the first protective sublayer is not greater than 150 m 2 / g, for example, 100 to 150 m 2 / g, the specific surface area of ​​the second protective sublayer is greater than 150m 2 / g, for example, 150 to 200 m 2 / g.

[0051] Specifically, the protective agent may include a first carrier and a first active metal, wherein the first active metal may include one or more of nickel, cobalt, molybdenum, and tungsten, and the first carrier may include an amorphous porous material.

[0052] In some embodiments, the amorphous porous material may include one or more of aluminum oxide, amorphous silica aluminum, titanium dioxide, zirconium dioxide, silicon dioxide, Al2O3-SiO2 composite oxide, Al2O3-TiO2 composite oxide, Al2O3-ZrO2 composite oxide, ZrO2-TiO2 composite oxide, and TiO2-SiO2 composite oxide.

[0053] Specifically, the mass of the main active metal in the protective agent accounts for a percentage of 0 to 10% of the mass of the protective agent, for example, 0% (i.e., the protective agent does not contain the main active metal), 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% or a range consisting of any two of them.

[0054] Generally speaking, when the protective agent contains the main active metal (that is, the mass percentage of the main active metal is not 0), the protective layer also has certain desulfurization, denitrification and demetallization functions, which is beneficial to further improve the hydrocracking efficiency.

[0055] When the protective layer includes at least two protective sublayers, the type of the carrier, the type of the main active metal, and the mass percentage of the main active metal in these protective sublayers may be the same or different.

[0056] In some embodiments, the mass percentage of the main active metal of the protective agent in the protective layer remains unchanged or shows an increasing trend along the material flow direction in the hydrogenation reactor. The increasing trend may include a gradual increase or a gradient increase, that is, the mass percentage of the first active metal of the protective agent in the protective layer may remain unchanged, gradually increase, or increase gradiently along the material flow direction in the hydrogenation reactor.

[0057] Specifically, when the protective layer includes at least two protective sub-layers, the mass percentage of the main active metal in each protective sub-layer may remain unchanged or show an increasing trend along the material flow direction.

[0058] Exemplarily, the mass percentage of the main active metal in each protective sublayer is basically the same (i.e., unchanged) along the material flow direction, and the mass percentage of the first active metal in any two adjacent ones of these protective sublayers is basically the same, thereby making the mass percentage of the main active metal of the protective agent in the protective layer unchanged along the material flow direction in the hydrogenation reactor; or, among these protective sublayers, the mass percentage of the main active metal in the protective sublayer closer to the catalyst layer is higher, thereby making the mass percentage of the main active metal in the protective agent in the protective layer tend to increase.

[0059] Exemplarily, the protective agent in the first protective sublayer does not contain the first active metal (i.e., the mass percentage of the first active metal therein is 0), and the mass percentage of the second active metal in the protective agent in the second protective sublayer is 0 or greater than 0, for example, 5 to 10%, but not limited to this.

[0060] In the above-mentioned grading method, the total acid content of the catalyst in the catalyst layer shows an increasing trend along the material flow direction in the hydrogenation reactor, and the increase in the increasing trend may specifically be a gradual increase or a gradient increase.

[0061] Specifically, the catalyst layer may include at least two catalytic sub-layers distributed in sequence along the material flow direction in the hydrogenation reactor, the total acid amount of the catalyst in each catalytic sub-layer may remain unchanged or show an increasing trend, and the total acid amount distribution of the catalyst in these catalytic sub-layers satisfies that the total acid amount of the catalyst in the catalyst layer shows an increasing trend along the material flow direction in the hydrogenation reactor.

[0062] For example, the above-mentioned catalyst layer includes three catalytic sublayers, namely the first catalytic sublayer, the second catalytic sublayer and the third catalytic sublayer. The protective layer, the first catalytic sublayer, the second catalytic sublayer and the third catalytic sublayer are distributed in sequence along the material flow direction. The total acid amount of the catalyst in the first catalytic sublayer is lower than the total acid amount of the catalyst in the second catalytic sublayer, and the total acid amount of the catalyst in the second catalytic sublayer is lower than the total acid amount of the catalyst in the third catalytic sublayer, thereby making the total acid amount of the catalyst in the catalyst layer increase along the material flow direction.

[0063] In the above grading method, the amount of strong acid and medium-strong acid in the catalyst layer accounts for the total acid amount of the catalyst and shows an increasing trend along the material flow direction. The increase in the increasing trend can specifically be a gradual increase or a gradient increase.

[0064] Specifically, the catalyst layer may include at least two catalytic sub-layers distributed in sequence along the material flow direction in the hydrogenation reactor, the sum of the strong acid content and the medium-strong acid content of the catalyst in each catalytic sub-layer may remain unchanged or show an increasing trend, and the sum of the strong acid content and the medium-strong acid content of the catalyst in these catalytic sub-layers accounts for the total acid content of the catalyst, and the sum of the strong acid content and the medium-strong acid content of the catalyst in the catalyst layer accounts for the total acid content of the catalyst and shows an increasing trend along the material flow direction in the hydrogenation reactor.

[0065] For example, the above-mentioned catalyst layer includes three catalytic sublayers, namely the first catalytic sublayer, the second catalytic sublayer and the third catalytic sublayer. The protective layer, the first catalytic sublayer, the second catalytic sublayer and the third catalytic sublayer are distributed in sequence along the material flow direction. The strong acid amount and medium-strong acid amount of the catalyst in the first catalytic sublayer accounts for a lower proportion of the total acid amount of the catalyst than the sum of the strong acid amount and medium-strong acid amount of the catalyst in the second catalytic sublayer accounts for a lower proportion of the total acid amount of the catalyst than the sum of the strong acid amount and medium-strong acid amount of the catalyst in the third catalytic sublayer. As a result, the sum of the strong acid amount and medium-strong acid amount of the catalyst in the catalyst layer accounts for an increasing trend of the total acid amount of the catalyst along the material flow direction.

[0066] The types of acids in the catalyst are divided into Acid and Lewis acid. According to the research of the inventors, the cracking activity of the catalyst can be further adjusted by appropriately adjusting the number and strength of the acid centers of the catalyst. However, the acid content of the catalyst will also affect the liquid yield. Excessive acid content and excessive acidity of the catalyst will aggravate the cracking reaction, resulting in a decrease in liquid yield and an increase in the generation of gas products. Insufficient acid content of the catalyst will lead to a low conversion rate of the raw material and a low yield of light oil products. Taking these factors into consideration, in order to take into account the effects of improving the conversion rate of the catalyst and the liquid yield of light oil products, in some preferred embodiments, the total acid content of the above-mentioned catalyst can be controlled to be 100-500 μmol / g, for example, 100 μmol / g, 120 μmol / g, 140 μmol / g, 160 mol / g, 180 μmol / g, 200 μmol / g, 220 μmol / g, 240 μmol / g, 250 μmol / g, 260 μmol / g. mol / g, 280 μmol / g, 300 μmol / g, 320 μmol / g, 340 μmol / g, 350 μmol / g, 360 μmol / g, 380 μmol / g, 400 μmol / g, 420 μmol / g, 440 μmol / g, 450 μmol / g, 460 μmol / g, 480 μmol / g, 490 μmol / g, 500 μmol / g or a range consisting of any two of them.

[0067] It can be understood that when the catalyst layer includes at least two catalytic sublayers (such as the first catalytic sublayer, the second catalytic sublayer and the third catalytic sublayer mentioned above), the total acid amount of the catalyst in each catalytic sublayer is 100 to 500 μmol / g, and the total acid amount of the catalyst in the catalyst layer shows an increasing trend along the material flow direction in the hydrogenation reactor.

[0068] Specifically, the difference in the total acid amount of the catalyst in two adjacent catalytic sublayers can be 10 to 300 μmol / g, for example, 10 μmol / g, 20 μmol / g, 30 μmol / g, 40 μmol / g, 50 μmol / g, 60 μmol / g, 70 μmol / g, 80 μmol / g, 90 μmol / g, 100 μmol / g, 110 μmol / g, 120 μmol / g, 130 μmol / g, 140 μmol / g , 150μmol / g, 160μmol / g, 170μmol / g, 180μmol / g, 190μmol / g, 200μmol / g, 210μmol / g, 220μmol / g, 230μmol / g, 240μmol / g, 250μmol / g, 260μmol / g, 270μmol / g, 280μmol / g, 290μmol / g, 300μmol / g or a range consisting of any two of them. Exemplarily, the difference between the total acid amount of the catalyst in the first catalytic sublayer and the total acid amount of the catalyst in the second catalytic sublayer can be 10 to 300mmol / g, and the difference between the total acid amount of the catalyst in the second catalytic sublayer and the total acid amount of the catalyst in the third catalytic sublayer can be 50 to 200μmol / g.

[0069] Further research has shown that the sum of the strong acid content and the medium-strong acid content of the catalyst in the above-mentioned catalyst layer accounts for the total acid content of the catalyst and shows an increasing trend along the material flow direction in the hydrogenation reactor. The increase can specifically be a gradual increase or a gradient increase.

[0070] In some preferred embodiments, the sum of the strong acid content and the medium-strong acid content of the above-mentioned catalyst can account for 70% to 90% of the total acid content of the catalyst, for example, 40%, 43%, 45%, 48%, 50%, 55%, 60%, 65%, 70%, 73%, 75%, 78%, 80%, 83%, 85%, 90% or a range consisting of any two of them.

[0071] It can be understood that when the catalyst layer includes at least two catalytic sublayers (such as the first catalytic sublayer, the second catalytic sublayer and the third catalytic sublayer mentioned above), the sum of the strong acid content and the medium-strong acid content of the catalyst in each catalytic sublayer accounts for 40% to 90% of the total acid content of the catalyst, and the sum of the strong acid content and the medium-strong acid content of the catalyst in the catalyst layer accounts for the total acid content of the catalyst and shows an increasing ratio along the material flow direction in the hydrogenation reactor.

[0072] Specifically, the difference in the proportion of the sum of the strong acid and the medium-strong acid in two adjacent catalytic sublayers to the total acid content of the catalyst can be 2 to 10%, for example, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% or a range consisting of any two of them.

[0073] It has been found that although too much strong acid in the catalyst can promote the improvement of hydrocracking activity, it is not conducive to the long-term operation of the catalyst, and will also lead to a decrease in liquid yield and the generation of more low-value-added gas products. Through experimental research, it was determined that the amount of strong acid in the catalyst is 30 to 150 μmol / g, for example, 30 μmol / g, 40 μmol / g, 50 μmol / g, 60 μmol / g, 70 μmol / g, 80 μmol / g, 90 μmol / g, 100 μmol / g, 110 μmol / g, 120 μmol / g, 130 μmol / g, 140 μmol / g, 150 μmol / g or a range consisting of any two of them.

[0074] Specifically, the difference in the amount of strong acid in two adjacent catalytic sublayers can be 20 to 100 μmol / g, for example, 20 μmol / g, 30 μmol / g, 40 μmol / g, 50 μmol / g, 60 μmol / g, 70 μmol / g, 80 μmol / g, 90 μmol / g, 100 μmol / g or a range consisting of any two of them.

[0075] The strong acid in the catalyst can moderately control the cracking activity of the catalyst and improve the distribution of the products. The amount of the strong acid in the catalyst is 50 to 300 μmol / g, for example, 50 μmol / g, 60 μmol / g, 70 μmol / g, 80 μmol / g, 90 μmol / g, 100 μmol / g, 110 μmol / g, 120 μmol / g, 130 μmol / g, 140 μmol / g, 150 μmol / g, 160 μmol / g, 170 μmol / g, 180 μmol / g, 190 μmol / g, 200 μmol / g, 210 μmol / g, 220 μmol / g, 230 μmol / g, 240 μmol / g, 250 μmol / g, 260 μmol / g, 270 μmol / g, 2 The invention relates to an aqueous solution of at least one iodine-containing compound and a aqueous solution of at least one iodine-containing compound. The aqueous solution of at least one iodine-containing compound can be selected from the group consisting of 0 μmol / g, 170 μmol / g, 180 μmol / g, 190 μmol / g, 200 μmol / g, 210 μmol / g, 220 μmol / g, 230 μmol / g, 240 μmol / g, 250 μmol / g, 260 μmol / g, 270 μmol / g, 280 μmol / g, 290 μmol / g, 300 μmol / g or a range consisting of any two of them.

[0076] The excess of strong acid in the catalyst bed can effectively control the cracking depth and avoid the generation of excessive gas products, which will lead to poor economic benefits of the device. The amount of medium-strong acid in the catalyst bed is 20 to 150 μmol / g higher than the amount of strong acid, for example, 20 μmol / g, 30 μmol / g, 40 μmol / g, 50 μmol / g, 60 μmol / g, 70 μmol / g, 80 μmol / g, 90 μmol / g, 100 μmol / g, 110 μmol / g, 120 μmol / g, 130 μmol / g, 140 μmol / g, 150 μmol / g or a range consisting of any two of them.

[0077] Specifically, the acid in the catalyst can be divided into weak acid, medium-strong acid and strong acid according to the acid strength. The weak acid amount of the catalyst is the amount of weak acid, and the total acid amount of the catalyst is the sum of the amounts of weak acid, medium-strong acid and strong acid in the catalyst. The present invention can determine the acid amount and acid strength of the catalyst by conventional methods in the art, for example, the acid amount and acid strength of the catalyst are determined by an ammonia temperature-programmed desorption (NH3-TPD) characterization method. On the NH3-TPD desorption chart, the amount of ammonia desorbed between 100°C and 230°C corresponds to the amount of weak acid, the amount of ammonia desorbed between 230°C and 370°C corresponds to the amount of medium-strong acid, and the amount of ammonia desorbed above 370°C corresponds to the amount of strong acid. The specific operation method can generally include: purging the catalyst sample with helium at 500°C for 1 hour and then cooling it to 60°C, introducing saturated ammonia vapor, and pulse adsorption five times to reach equilibrium; heating to 100°C and purging for 2 hours, then performing ammonia desorption at a heating rate of 10°C / min, and heating to 650°C; absorbing the desorbed ammonia with a hydrochloric acid solution, and then titrating the excess hydrochloric acid with a sodium hydroxide solution, and defining the amount of weak acid, medium-strong acid, strong acid and total acid of the catalyst according to the amount of hydrochloric acid consumed by absorbing ammonia.

[0078] In addition, the mass percentage of the main active metal in the catalyst in the catalyst layer shows an increasing trend along the material flow direction in the hydrogenation reactor, and the increasing trend may specifically include a gradual increase or a gradient increase.

[0079] When the catalyst layer includes at least two catalyst sublayers, the mass percentage of the main active metal of the catalyst in each catalyst sublayer may remain unchanged or increase along the material flow direction. In some specific embodiments, in two adjacent catalyst sublayers, the mass percentage of the main active metal of the catalyst in the upstream one is less than the mass percentage of the main active metal of the catalyst in the downstream one, that is, the mass percentage of the main active metal of the catalyst in the catalyst sublayer farther away from the protective layer is greater, thereby causing the mass percentage of the main active metal of the catalyst in the catalyst layer to gradually increase or increase in gradient along the material flow direction in the hydrogenation reactor.

[0080] For example, the mass percentage of the main active metal of the catalyst in the first catalytic sublayer is less than the mass percentage of the main active metal of the catalyst in the second catalytic sublayer, and the mass percentage of the main active metal of the catalyst in the second catalytic sublayer is less than the mass percentage of the main active metal of the catalyst in the third catalytic sublayer, thereby making the mass percentage of the main active metal of the catalyst in the catalyst layer gradually increase or gradient increase along the direction of material flow.

[0081] Specifically, the mass percentage of the main active metal in the above-mentioned catalyst can be 20-40% (that is, the mass of the main active metal accounts for 20-40% of the total mass of the catalyst), for example, 20%, 25%, 30%, 35%, 40% or a range composed of any two of them, and the main active metal includes one or more of Co, Mo, Ni and W.

[0082] It can be understood that when the catalyst layer includes at least two catalytic sublayers (such as the first catalytic sublayer, the second catalytic sublayer and the third catalytic sublayer mentioned above), the mass percentage of the main active metal of the catalyst in each catalytic sublayer is 20-40%, and the mass percentage of the main active metal of the catalyst in the catalyst layer shows an increasing trend along the material flow direction in the hydrogenation reactor.

[0083] Specifically, the difference in the mass percentage of the main active metal of the catalyst in two adjacent catalytic sublayers (such as the first catalytic sublayer and the second catalytic sublayer, or the second catalytic sublayer and the third catalytic sublayer, etc.) can be 5-15%, for example, 5%, 6%, 7%, 8%, 9%, 18%, 10%, 11%, 12%, 13%, 14%, 15% or a range consisting of any two of them.

[0084] In addition, the pore volume of the above catalyst can be 0.2-0.6 ml / g, such as 0.2 ml / g, 0.3 ml / g, 0.4 ml / g, 0.5 ml / g, 0.6 ml / g or any two of them. It is understood that when the catalyst layer includes at least two catalyst sublayers (such as the first catalyst sublayer, the second catalyst sublayer and the third catalyst sublayer), the pore volume of the catalyst in each catalyst sublayer can be 0.2-0.6 ml / g, respectively, and the pore volume of the catalyst in these catalyst sublayers can be the same or different.

[0085] In addition, the above catalyst also includes a carrier, and the carrier may include an inorganic porous material, and the inorganic porous material may specifically be an amorphous porous material.

[0086] In some embodiments, the amorphous porous material may include one or more of alumina, amorphous silica alumina (ASA), titanium dioxide, zirconium dioxide, silicon dioxide, Al2O3-SiO2, Al2O3-TiO2 composite oxide, Al2O3-ZrO2 composite oxide, ZrO2-TiO2 composite oxide, and TiO2-SiO2 composite oxide.

[0087] In addition, the mass percentage of the amorphous porous material in the catalyst can be 5-27% (i.e., the mass of the amorphous porous material accounts for 5-27% of the total mass of the catalyst), for example, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27% or any two thereof. The mass percentage of the molecular sieve in the catalyst is 50-70% (that is, the mass of the molecular sieve accounts for 50-70% of the total mass of the catalyst), for example, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70% or the range composed of any two of them.

[0088] In addition, the above-mentioned catalyst may also include an acidic auxiliary agent. The mass percentage of the acidic auxiliary agent in the catalyst may be 0.5-3% (i.e., the mass of the acidic auxiliary agent accounts for 0.5-3% of the total mass of the catalyst), for example, 0.5%, 0.6%, 0.7%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3% or a range consisting of any two of them.

[0089] Specifically, the acidic auxiliary agent may include one or more of phosphoric acid, boric acid, hydrofluoric acid, nitric acid, citric acid, tartaric acid, and malic acid.

[0090] When the catalyst layer includes at least two catalytic sub-layers, the type of the main active metal of the catalyst in these catalytic sub-layers, the mass percentage of the main active metal, the type and mass percentage of the carrier (inorganic material / molecular sieve), the type and mass percentage of the acidic auxiliary agent, the type and mass percentage of the acidic auxiliary agent, etc. can be the same or different.

[0091] In addition, the volume of the above-mentioned protective layer can account for 2 to 20% of the sum of the volume of the protective layer and the volume of the catalyst layer, for example, 2%, 3%, 4%, 5%, 7%, 10%, 12%, 15%, 18%, 20% or a range consisting of any two of them, and the volume of the catalyst layer can account for 80 to 98% of the sum of the volume of the protective layer and the volume of the catalyst layer, for example, 80%, 82%, 85%, 88%, 90%, 93%, 95%, 98% or a range consisting of any two of them.

[0092] Generally, in the above-mentioned protective layer and catalyst layer, the volume proportion of the protective layer is basically equal to the proportion of its length (or thickness) in the material flow direction, and the volume proportion of the catalyst layer is basically equal to the proportion of its length (or thickness) in the material flow direction, that is, the length (thickness) of the protective layer in the material flow direction is L1, and the length (thickness) of the catalyst layer in the material flow direction is L2, L1 / (L1+L2) is equal to the ratio of the volume of the above-mentioned protective layer to the sum of the volume of the protective layer and the volume of the catalyst layer, that is, L1 / (L1+L2) is 2~20%, L2 / (L1+L2) is equal to the ratio of the volume of the above-mentioned catalyst layer to the sum of the volume of the protective layer and the volume of the catalyst layer, that is, L2 / (L1+L2) is 80~98%.

[0093] When the protective layer includes at least two protective sublayers, the volume of the protective layer refers to the sum of the volumes of these protective sublayers, and the length (thickness) of the protective layer refers to the sum of the lengths (thicknesses) of these protective sublayers; when the catalyst layer includes at least two catalytic sublayers, the volume of the catalyst layer refers to the sum of the volumes of these catalytic sublayers, and the length (thickness) of the catalyst layer refers to the sum of the lengths (thicknesses) of these catalytic sublayers.

[0094] When the protective layer includes at least two protective sublayers, the ratio of the volume of each of these protective sublayers to the sum of the volume of the protective layer and the volume of the catalyst layer may be the same or different. Exemplarily, when the protective layer includes a first protective sublayer and a second protective sublayer, the ratio of the volume of the first protective sublayer to the sum of the volume of the protective layer and the volume of the catalyst layer is a1, and the ratio of the volume of the second protective sublayer to the sum of the volume of the protective layer and the volume of the catalyst layer is a2, a1 may be greater than, equal to or less than a2, and exemplarily, a1 and a2 may be 2 to 15%, respectively, for example, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15% or a range consisting of any two of them.

[0095] When the protective layer includes at least two catalytic sublayers, the ratio of the volume of each of these catalytic sublayers to the sum of the volume of the protective layer and the volume of the catalyst layer may be the same or different. Exemplarily, when the catalyst layer includes a first catalytic sublayer, a second catalytic sublayer and a third catalytic sublayer, the ratio of the volume of the first catalytic sublayer to the sum of the volume of the protective layer and the volume of the catalyst layer is b1, the ratio of the volume of the second catalytic sublayer to the sum of the volume of the protective layer and the volume of the catalyst layer is b2, the ratio of the volume of the third catalytic sublayer to the sum of the volume of the protective layer and the volume of the catalyst layer is b3, b1 may be greater than, equal to or less than b2, b2 may be greater than, equal to or less than b3, b1 may be greater than, equal to or less than b3, and exemplarily, b1, b2, and b3 may be 15 to 45%, respectively, such as 15%, 20%, 25%, 30%, 35%, 40%, 45% or a range consisting of any two of them.

[0096] The hydrogenation reactor of the embodiment of the present invention can be a conventional structure in the art, wherein each protective sublayer and each catalytic sublayer are respectively a bed layer of the hydrogenation reactor, that is, the hydrogenation reactor can have a multi-layer bed layer consisting of at least two protective sublayers and at least two catalytic sublayers, and any two adjacent beds can be separated by structures such as tower plates, distribution plates for distributing fillers (such as protective agents or catalysts, etc.) into the hydrogenation reactor to form a bed layer, etc.

[0097] The oil product hydrocracking method provided in an embodiment of the present invention comprises: allowing the oil product to be treated to enter a hydrogenation reactor and contact with a protective agent and a catalyst for hydrocracking, wherein the protective agent and the catalyst in the hydrogenation reactor are loaded according to the above-mentioned grading method, and the flow direction of the oil product to be treated in the hydrogenation reactor is the material flow direction in the hydrogenation reactor, that is, after the oil product to be treated enters the hydrogenation reactor, it first flows through the protective layer and then flows through the catalyst layer.

[0098] Generally, the above-mentioned hydrocracking reaction is carried out in the presence of hydrogen. Specifically, the oil product to be treated can be mixed with hydrogen and then enter into a hydrogenation reactor, and contact with a protective agent and a catalyst in sequence for hydrocracking. In the hydrocracking process, desulfurization, denitrogenation, aromatic saturation, cracking and ring opening, long-chain alkane cleavage and other reactions are carried out to achieve lightening of the oil product to be treated, as well as desulfurization, denitrogenation and other treatments, and can also take into account improving the liquid yield of light products, especially the yield of naphtha.

[0099] In some embodiments, the conditions of the above-mentioned hydroprocessing can be: the reaction pressure is 6 to 15 MPa, for example, 6 MPa, 7 MPa, 8 MPa, 9 MPa, 10 MPa, 11 MPa, 12 MPa, 13 MPa, 14 MPa, 15 MPa or a range consisting of any two thereof; the reaction temperature is 300 to 400°C, for example, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C, 400°C or a range consisting of any two thereof; the volume space velocity is 0.5 to 2.0 h -1 , for example 0.5h -1 、0.8h -1 , 1h -1 , 1.2h -1 , 1.5h -1 , 1.8h -1 , 2h -1 Or a range consisting of any two of them, the volume ratio of hydrogen to oil is (100-1000):1, for example 100:1, 200:1, 300:1, 400:1, 500:1, 600:1, 700:1, 800:1, 900:1, 1000:1 or a range consisting of any two of them.

[0100] In some embodiments, the sulfur mass in the treated oil is no more than 1000 μg / g, for example, 10 μg / g, 30 μg / g, 50 μg / g, 80 μg / g, 100 μg / g, 150 μg / g, 200 μg / g, 250 μg / g, 300 μg / g, 350 μg / g, 400 μg / g, 450 μg / g, 500 μg / g, 600 μg / g, 700 μg / g, 800 μg / g, 900 μg / g, 1000 μg / g or a combination thereof. The range composed of any two of them, the mass of nitrogen in the oil to be treated is not more than 20μg / g, for example, 1μg / g, 2μg / g, 3μg / g, 4μg / g, 5μg / g, 6μg / g, 7μg / g, 8μg / g, 9μg / g, 10μg / g, 11μg / g, 12μg / g, 13μg / g, 14μg / g, 15μg / g, 16μg / g, 17μg / g, 18μg / g, 19μg / g, 20μg / g or the range composed of any two of them.

[0101] The above-mentioned oil products to be processed may include wax oil, specifically one or more of coker gas oil (CGO), vacuum gas oil (VGO), coker diesel and wax oil. The hydrocracking method of the embodiment of the present invention can improve the desulfurization, denitrogenation and light oil yield of these oil products to be processed, especially the naphtha yield.

[0102] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0103] In the following Examples 1 to 3 and Comparative Examples 1 to 3, vacuum gas oil (VGO) is used as the feedstock oil (oil product to be treated), which is mixed with hydrogen and then enters the hydrogenation reactor to flow through the protective layer and the catalyst layer in sequence for hydrogenation reaction treatment. The properties of the feedstock oil are shown in Table 1.

[0104] Table 1 Raw oil properties

[0105]

[0106] In the following Examples 1 to 3 and Comparative Examples 1 to 2, the feedstock oil flows from top to bottom in the hydrogenation reactor (i.e., the material flow direction in the hydrogenation reactor is from top to bottom); in the hydrogenation reactor, the protective layer includes a first protective sublayer (upper protective layer) and a second protective sublayer (lower protective layer), and the catalyst layer includes a first catalytic sublayer (upper catalyst layer), a second catalytic sublayer (middle catalyst layer), and a third catalytic sublayer (lower catalyst layer), and the upper protective layer, the lower protective layer, the upper catalyst layer, the middle catalyst layer, and the lower catalyst layer are sequentially distributed along the material flow direction;

[0107] The pore volume, specific surface area, carrier, main active metal type and content, filling ratio (the ratio of the volume of each protective sublayer to the sum of the volume of the protective layer and the volume of the catalyst layer) of each protective sublayer of each embodiment and comparative example, as well as the main active metal type and content of each catalytic sublayer, the type and content of amorphous porous material, the type and content of molecular sieve, acidic additive and its content, the ratio of the sum of the total acid amount, strong acid amount and medium-strong acid amount to the total acid amount of the catalyst, pore volume, and filling ratio (the ratio of the volume of each catalytic sublayer to the sum of the volume of the protective layer and the volume of the catalyst layer) are shown in Table 2; wherein the contents are all in percentage by mass.

[0108] Among them, in Comparative Example 1, a single protective agent is used (i.e., different protective agents are used for the upper protective layer and the lower protective layer), and the total acid amount of the catalyst layer remains unchanged along the material flow direction (i.e., the total acid amount of the catalyst in the upper catalyst layer, the middle catalyst layer, and the lower catalyst layer is the same), and the sum of the strong acid amount and the medium-strong acid amount accounts for the same proportion of the total acid amount of the catalyst (i.e., the sum of the strong acid amount and the medium-strong acid amount in the upper catalyst layer, the middle catalyst layer, and the lower catalyst layer accounts for the same proportion of the total acid amount of the catalyst);

[0109] Among them, in Comparative Example 2, a single protective agent is used (i.e., the upper protective layer and the lower protective layer use the same protective agent), and the total acid amount of the catalyst layer decreases along the material flow direction (i.e., the total acid amount of the catalyst in the upper catalyst layer, the middle catalyst layer and the lower catalyst layer decreases successively), and the proportion of the sum of the strong acid amount and the medium-strong acid amount to the total acid amount of the catalyst is the same (i.e., the proportion of the sum of the strong acid amount and the medium-strong acid amount in the upper catalyst layer, the middle catalyst layer and the lower catalyst layer to the total acid amount of the catalyst decreases successively).

[0110] In addition, the hydrogenation treatment conditions in the hydrogenation reactor in each embodiment and the comparative example are the same, specifically: the reaction temperature is 380°C, the reaction pressure is 15MPa, the liquid hourly volume space velocity is 1.2h -1 , the volume ratio of hydrogen to oil is 500:1.

[0111] In addition, the hydrocracking product results of each embodiment and comparative example are shown in Table 3 (including sulfur content, nitrogen content, kerosene liquid yield, and naphtha liquid yield.

[0112] Table 2 Catalyst grading in hydrogenation reactor

[0113]

[0114]

[0115] Table 3 Properties of hydrocracking products

[0116] Analyze Project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Sulfur, μg / g 3 4 3 4 12 Nitrogen, μg / g 1 1 1 2 5 Kerosene yield, wt% 32 36 37 41 31 Naphtha yield, wt% 59 57 58 43 35 Total liquid yield, wt% 97.5 96.2 97.4 86.1 95.4 Gas yield, wt% 2.5 3.8 2.6 13.9 5.6

[0117] It can be seen that compared with Comparative Examples 1 to 2, the sulfur and nitrogen contents of the products in Examples 1 to 3 are lower. The present invention can significantly improve the total liquid yield of the device, reduce the yield of gas products, and increase the yield of light oil products (kerosene and naphtha), especially the naphtha yield is relatively high. Petroleum oil is a high-quality ethylene cracking raw material. Increasing the naphtha yield can effectively improve the economic benefits of the device. At the same time, as a low value-added product, the low yield of gas can further improve the economic benefits of the device.

[0118] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for treating oil products by hydrocracking, characterized in that: The treatment method adopts a grading process of a hydrocracking catalyst, and the grading process comprises: sequentially filling a protective layer and a catalyst layer in the hydrogenation reactor along the material flow direction in the hydrogenation reactor; The protective layer includes a protective agent, and the pore volume of the protective agent in the protective layer tends to decrease along the material flow direction in the hydrogenation reactor; the protective agent includes a carrier and a main active metal; The catalyst layer includes a catalyst, the total acid amount of the catalyst in the catalyst layer shows an increasing trend along the material flow direction in the hydrogenation reactor; the ratio of the sum of the acid amount of the strong acid and the medium-strong acid to the total acid amount shows an increasing trend along the material flow direction in the hydrogenation reactor; the catalyst includes a carrier and a main active metal; The total acid amount of the catalyst in the catalyst layer is 100-500 μmol / g; the strong acid amount of the catalyst in the catalyst layer is 30-150 μmol / g; The amount of strong acid in the catalyst of the catalyst layer is 50-300 μmol / g; In the catalyst of the catalyst layer, the amount of the medium-strong acid is 20 to 150 μmol / g higher than the amount of the strong acid; The content of the main active metal in the catalyst tends to increase along the material flow direction in the hydrogenation reactor; The treatment method comprises: allowing the oil product to be treated to enter a hydrogenation reactor and contact with a protective agent and a catalyst for hydrocracking, wherein the protective agent and the catalyst in the hydrogenation reactor are loaded according to the grading process, and the flow direction of the oil product to be treated in the hydrogenation reactor is the material flow direction in the hydrogenation reactor; The conditions of the treatment method are: reaction pressure of 6-15 MPa, reaction temperature of 300-400°C, volume space velocity of 0.5-2.0 h -1 , the volume ratio of hydrogen to oil is (100~1000):1; And / or, the oil product to be treated includes one or more of coker gas oil, vacuum gas oil, coker diesel oil and wax oil; And / or, the sulfur content in the oil product to be treated is not more than 1000 μg / g; and / or, the nitrogen content in the oil product to be treated is not more than 20 μg / g.

2. The oil hydrocracking treatment method according to claim 1, characterized in that: The pore volume of the protective agent in the protective layer shows a gradually decreasing trend along the material flow direction in the hydrogenation reactor; and / or the specific surface area of ​​the protective agent in the protective layer shows an increasing trend along the material flow direction in the hydrogenation reactor, and the increasing trend is a gradually increasing trend; The total acid amount of the catalyst in the catalyst layer shows a gradually increasing trend along the material flow direction in the hydrogenation reactor.

3. The oil hydrocracking treatment method according to claim 1 or 2, characterized in that: The pore volume of the protective agent is not less than 0.5 mL / g.

4. The oil hydrocracking treatment method according to claim 1, characterized in that: The mass percentage of the main active metal in the protective agent is 1-10% of the mass of the protective agent; the main active metal in the protective agent is selected from one or more of nickel, cobalt, molybdenum and tungsten; The protective agent carrier comprises an inorganic porous material, and the inorganic porous material comprises one or more of alumina, amorphous silica-alumina, titanium dioxide, zirconium dioxide, silicon dioxide, Al2O3-SiO2 composite oxide, Al2O3-TiO2 composite oxide, Al2O3-ZrO2 composite oxide, ZrO2-TiO2 composite oxide, and TiO2-SiO2 composite oxide; The mass percentage of the main active metal of the protective agent in the protective layer remains unchanged or shows an increasing trend along the material flow direction in the hydrogenation reactor, and the increasing trend is a gradual increase.

5. The oil hydrocracking treatment method according to claim 1, characterized in that: The catalysis The carrier of the catalyst comprises an amorphous porous material and a molecular sieve, wherein the amorphous porous material comprises one or more of alumina, amorphous silica-alumina, titanium dioxide, zirconium dioxide, silicon dioxide, Al2O3-SiO2, Al2O3-TiO2 composite oxide, Al2O3-ZrO2 composite oxide, ZrO2-TiO2 composite oxide, and TiO2-SiO2 composite oxide; the molecular sieve comprises one or more of Y molecular sieve, ZSM-5, ZSM-22, ZSM-23, ZSM-35, Beta, and ZSM-48; the mass percentage of the amorphous porous material in the catalyst is 5-27%, and the mass percentage of the molecular sieve in the catalyst is 50-70%; The mass percentage of the main active metal in the catalyst is 20-40% of the mass of the catalyst; and / or, the main active metal in the catalyst is selected from one or more of nickel, cobalt, molybdenum and tungsten; And / or, the catalyst further includes an acidic auxiliary agent, wherein the mass percentage of the acidic auxiliary agent in the catalyst is 0.5-3%, and the acidic auxiliary agent includes one or more of phosphoric acid, boric acid, hydrofluoric acid, nitric acid, citric acid, tartaric acid, and malic acid.

6. The oil hydrocracking treatment method according to claim 1, characterized in that: The ratio of the sum of the acid amount of the strong acid and the medium-strong acid to the total acid amount gradually increases along the material flow direction in the hydrogenation reactor; And / or, the pore volume of the catalyst is 0.2-0.6 mL / g.

7. The oil hydrocracking treatment method according to claim 1, characterized in that: The volume of the protective layer accounts for 2-20% of the sum of the volume of the protective layer and the volume of the catalyst layer, and / or the volume of the catalyst layer accounts for 80-98% of the sum of the volume of the protective layer and the volume of the catalyst layer.

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